Shashanka Doddamani

Aim of the Project

 

                           To build a simple and low cost DC Uninterruptible Power Supply for low power real time embedded systems that grants immunity to transient power failures.

 

Tools and Hardware Used

 

Software:  

      TINA - Texas Instruments' Circuit                   

      Simulation Software                                         

      OrCAD - Schematics and Layout  Design of   PCBs                                                   

                                                                          

Hardware:                                                        

      IC's used: LM 358, TL 2575 series of switching regulators

      Lead Acid Batteries - 6V, 1.3 Ah each

      Step Down Transformer - 240V/15V, 2A

 

 

 

Project Synopsis

 

           Despite the ocean of papers in IEEE about smart domestic automation and innovative low power real time systems, very few, or nearly none have made it into the society of developing countries. One of the reasons is frequent power cuts. Embedded Real time systems need to operate round the clock, so I selectively teamed up with 3 of my classmates to make a simple low cost DC UPS. We made a working circuit that incorporates a battery monitor and charger using the concepts of Linear Integrated Circuits and Analog Electronics. We used schmitt trigger, an anlog memory element as a battery monitor to store 2 different analog voltages and detect the time to charge and discharge the battery.  

           

            The switching between mains and battery was accomplished through 2 ways. The first one was using a relay that isolates the filter capacitor from the circuit enabling instantaneous switching to the battery. The second was through active switching using a voltage comparator. The former design was presented as a paper in an IEEE conference, while the latter was developed subsequently and overcame a few drawbacks of the former; this powered our most ambitious and successful project to date, the Safest key - Smart Key.

 

 

Result

 

               We were able to infer the expected results, and as a first author I presented a paper titled 'A Low Cost DC Uninterruptible Power Supply with Capacitor Isolation' at IEEE International Conference on Control System, Computing and Engineering (ICCSCE 2012), Penang, Malaysia.